Conventionally, in a communication system, a communication apparatus performing wireless communication may execute scanning for searching for a connection destination. For example, in such a communication system, when a communication apparatus searches for (scans) other communication apparatuses around the communication apparatus, the communication apparatus (hereinafter, a communication apparatus that searches for other communication apparatuses is referred to as a search communication apparatus) transmits a search request signal (probe request) to other communication apparatuses (hereinafter, a communication apparatus that is searched for is referred to as a search subject communication apparatus) by broadcast. Then, a search subject communication apparatus that has received the search request signal transmits a search response signal (probe response) indicating the presence of the search subject communication apparatus, as a response to the search request signal, to the search communication apparatus which has transmitted the search request signal. Then, the search communication apparatus receives the search response signal, thereby recognizing the presence of the search subject communication apparatus.
However, in such a communication system as described above, in order to find a large number of other communication apparatuses, the search communication apparatus is to sequentially receive search response signals respectively transmitted from the large number of other communication apparatuses, and therefore, it takes long time for the searching. That is, the search communication apparatus cannot search for a large number of other communication apparatuses in a short period. Therefore, the efficiency of the searching cannot be increased.
Therefore, a feature of the exemplary embodiments provides a communication system, a communication apparatus, a computer-readable storage medium having stored therein a communication program, and a communication method that have increased efficiency of searching when a communication apparatus searches for another communication apparatus.
The exemplary embodiments have the following aspects in order to solve the above problem.
A communication system according to one aspect of the exemplary embodiments includes: a search communication apparatus which searches for another communication apparatus; and a plurality of search subject communication apparatuses which are searched for by the search communication apparatus. The search communication apparatus comprises a search request transmission section configured to transmit a search request signal. The search subject communication apparatuses each comprises: a search request reception section configured to receive the search request signal transmitted from the search communication apparatus; a search response transmission section configured to transmit a search response signal which is a response to the search request signal received by the search request reception section, to the search communication apparatus; and a search response monitoring section configured to monitor the search response signal transmitted from another search subject communication apparatus to the search communication apparatus. The search communication apparatus further comprises a search response reception section configured to receive the search response signal transmitted from the search subject communication apparatus. The search response transmission section transmits, as a proxy response signal, to the search communication apparatus, the search response signal monitored by the search response monitoring section, which has been transmitted from the other search subject communication apparatus. The search response reception section receives the proxy response signal in addition to the search response signal.
According to the above aspect, the search subject communication apparatus monitors search response signals transmitted from other search subject communication apparatuses to the search communication apparatus, and transmits the monitored search response signals as a proxy response signal, to the search communication apparatus. Therefore, the search communication apparatus can recognize the presences of a plurality of search subject communication apparatuses by receiving a proxy response signal transmitted from one search subject communication apparatus. Thus, the efficiency of searching is increased.
In another aspect, the proxy response signal may be one signal obtained by integrating the search response signal transmitted from the search subject communication apparatus to the search communication apparatus, and the search response signal monitored by the search response monitoring section, which has been transmitted from the other search subject communication apparatus.
According to the above aspect, the proxy response signal is transmitted including several signals integrated. Therefore, the search communication apparatus can recognize the presences of a plurality of search subject communication apparatuses by only receiving the one proxy response signal. That is, the search communication apparatus can recognize the presences of a plurality of search subject communication apparatuses in a shorter reception time than the total reception time for sequentially receiving search response signals transmitted from the search subject communication apparatuses. Therefore, the search communication apparatus can recognize the presences of a plurality of search subject communication apparatuses in a shorter period, and thus, the efficiency of searching is increased.
In another aspect, the search response monitoring section may monitor the proxy response signal transmitted from another search subject communication apparatus. In this case, when the search response signal transmitted from the search subject communication apparatus is included in the proxy response signal monitored by the search response monitoring section of the search subject communication apparatus, the search response transmission section of the search subject communication apparatus does not transmit the search response signal.
According to the above aspect, if a search response signal of a search subject communication apparatus is included in a proxy response signal transmitted from another search subject communication apparatus, the search subject communication apparatus does not transmit a search response signal. Therefore, the search communication apparatus can avoid redundantly receiving the same search response signals. Thus, the efficiency of searching is increased.
In another aspect, the search subject communication apparatuses may each further comprise a priority setting section configured to set a priority of transmission of the search response signal. The priority setting section may set the priority as follows. If the search subject communication apparatus has transmitted the search response signal to the search communication apparatus at least one time, the priority setting section sets the priority to be lower than if the search subject communication apparatus has not transmitted the search response signal. In this case, the search response transmission sections of the search subject communication apparatuses transmit the search response signals in the order corresponding to the priorities that have been set.
According to the above aspect, the priority of transmission of a search response signal of a search subject communication apparatus that has transmitted a search response signal at least one time is set to be lower than the priority of a search subject communication apparatus that has not transmitted a search response signal. Therefore, a search subject communication apparatus that has not yet been recognized by the search communication apparatus preferentially transmits a search response signal in preference to other search subject communication apparatuses. Thus, the efficiency of searching by the search communication apparatus is increased.
In another aspect, the search subject communication apparatuses may each further comprise a priority setting section configured to set a priority of transmission of the search response signal. The priority setting section may set the priority as follows. The more the number of other search subject communication apparatuses that have transmitted the search response signals monitored by the search response monitoring section and included in the proxy response signal is, the higher the priority setting section sets the priority to be. In this case, the search response transmission sections of the search subject communication apparatuses transmit the search response signals in the order corresponding to the priorities that have been set.
According to the above aspect, the more the number of other search subject communication apparatuses that have transmitted search response signals included in a proxy response signal to be transmitted by a search subject communication apparatus is (that is, the more the number of other search subject communication apparatuses whose search response signals are to be transmitted by a search subject communication apparatus in place of the other search subject communication apparatuses is), the more preferentially a search response signal (the proxy response signal) of the search subject communication apparatus is transmitted. Therefore, the search communication apparatus can recognize the presences of a large number of search subject communication apparatuses in a short period, and thus, the efficiency of searching is increased.
In another aspect, the search subject communication apparatuses may each further comprise: a proxy registration section and a proxy deletion section. The proxy registration section registers, in a storage section of the search subject communication apparatus, information about the other search subject communication apparatus that has transmitted the search response signal monitored by the search response monitoring section. The proxy deletion section deletes the information about the other search subject communication apparatus which has been registered by the proxy registration section, from the storage section. In this case, the search response transmission section transmits the proxy response signal, based on the information about the other search subject communication apparatus registered in the storage section.
According to the above aspect, a search subject communication apparatus can appropriately manage pieces of information about other search subject communication apparatuses that have transmitted search response signals monitored by the search subject communication apparatus, and transmit a proxy response signal, based on the currently stored pieces of information about the other search subject communication apparatuses.
In another aspect, when a predetermined time has elapsed since the proxy registration section registered the information about the other search subject communication apparatus in the storage section, the proxy deletion section may delete the information about the other search subject communication apparatus from the storage section.
According to the above aspect, information about another search subject communication apparatus that has transmitted a search response signal monitored by the search subject communication apparatus is deleted from the storage section when a predetermined time has elapsed. Therefore, while transmitting a proxy response signal based on the currently stored pieces of information about other search subject communication apparatuses, the search subject communication apparatus can prevent cumulative increase in the number of proxy targets included in the proxy response signal (the number of search response signals of other search subject communication apparatuses for which proxy response is performed).
In another aspect, when the search response transmission section has transmitted, a predetermined number of times, as the proxy response signal, the search response signal monitored by the search response monitoring section, the proxy deletion section may delete the information about the other search subject communication apparatus that has transmitted the search response signal, from the storage section.
According to the above aspect, if a monitored search response signal has been transmitted as a proxy response signal a predetermined number of times, information about a search subject communication apparatus that has transmitted the monitored search response signal is deleted from the storage section. Therefore, while transmitting a proxy response signal based on the currently stored pieces of information about other search subject communication apparatuses, the search subject communication apparatus can avoid continuously transmitting, more than a predetermined number of times, a search response signal of another search subject communication apparatus that has been already transmitted as a proxy response signal the predetermined number of times.
In another aspect, when the search request reception section has received the search request signal, the search response monitoring section may start to monitor the search response signal transmitted from the other search subject communication apparatus.
According to the above aspect, when a search subject communication apparatus has recognized that the search communication apparatus is searching, the search subject communication apparatus starts to monitor search response signals transmitted from other search subject communication apparatuses. Therefore, the search subject communication apparatus can start the monitoring at an appropriate timing without unnecessary monitoring. As used herein, starting the monitoring means starting to receive a signal from a search subject communication apparatus and determine whether or not to transmit the signal as a proxy response signal.
In the above, the exemplary embodiments are described using a communication system as an example. However, the exemplary embodiments may be applied to a communication apparatus, a computer-readable storage medium having stored therein a communication program, or a communication method.
According to the exemplary embodiments, it is possible to provide a communication system and the like that have increased efficiency of searching when a communication apparatus searches for another communication apparatus.
These and other objects, features, aspects and advantages of the exemplary embodiments will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.